Music generated by a system component that has no discernible musical inputs. That is, "not transformational" (Rowe 1991; Lippe 1997:34; Winkler 1998). The Koan software by SSEYO – used by Brian Eno to create Generative Music 1 – is an example of this.

Non-deterministic music (Biles 2002), or music that cannot be repeated, for example, ordinary wind chimes (Dorin 2001). This perspective comes from the broader generative art movement. This revolves around the idea that music, or sounds may be "generated" by a musician "farming" parameters within an ecology, such that the ecology will perpetually produce different variation based on the parameters and algorithms used. An example of this technique is Joseph Nechvatal's Viral symphOny: a collaborative electronic noise music symphony[1] created between the years 2006 and 2008 using custom artificial life software based on a viral model.[2]

Many software programs have been written to create generative music, including:

SSEYO Koan Pro (1994–2007), used by Brian Eno to create his hybrid album Generative Music 1. The SSEYO Koan software was created by Pete Cole and Tim Cole of Intermorphic, who re-acquired the Koan technology in 2008. The software was displayed in the London Science Museum's Oramics exhibition (2011-2012) [1]

Intermorphic's Noatikl (2007–present). Noatikl is described by Intermorphic as "The Evolution of Koan", and was launched in 2007 as a replacement for the no-longer-available Koan. Noatikl is a generative music engine that generates MIDI events in accordance with a rule set that can be manipulated in real-time through a graphical user interface. Noatikl can operate as a Hyperinstrument by responding to incoming MIDI event data, with optional extension through user-supplied Lua scripts. Noatikl is available as a standalone tool for iOS, macOS and Windows, and there are VST and AU plug-ins for desktop music sequencers. Noatikl 2 was released in May 2012. Noatikl 3 for iOS, macOS and Windows was released in November 2015.

Intermorphic's Wotja (2014–present). Wotja is an app for iOS, which uses an integrated Noatikl music engine to allow a user to generate text-driven generative music messages.

Intermorphic's Tiklbox (2012–present). Tiklbox is an app for iOS, which uses an integrated Noatikl music engine to create ambient generative music, to assist in relaxation and reflection.

RoGame Software's Quincy (2014–present), a musical explorer of Life based on the cellular automaton created by John Horton Conway for iOS and macOS. Quincy is a full implementation of Life, capable of generating all possible variations, the common B3/S23 as well as others like HighLife or Seeds.

Staggered Laboratories is a generative development project focused on melodic compositions. The stack includes homegrown software that produces endless 24/7 audio streams in the pop and electronica genres.

Quasi Art - automatic program for generation quasi music (algorithm by Lois Alexandre, released 2016). The program creates unimaginable and bizarre orchestral melodies created programmatically using the built-in synthesizer in realtime.

Brian Eno, who coined the term generative music, has used generative techniques on many of his works, starting with Discreet Music (1975) up to and including (according to Sound on Sound Oct 2005) Another Day on Earth. His works, lectures, and interviews on the subject[4] have done much to promote generative music in the avant-garde music community. Eno used SSEYO'sKoan generative music system (created by Pete Cole and Tim Cole of Intermorphic), to create his hybrid album Generative Music 1 (published by SSEYO and Opal Arts in April 1996), which is probably his first public use of the term generative music.

Lerdahl and Jackendoff's publication described a generative grammar for homophonic tonal music, based partially on a Schenkerian model. While originally intended for analysis, significant research into automation of this process in software is being carried out by Keiji Hirata and others.

In It's Gonna Rain, an early work by contemporary composer Steve Reich, overlapping tape loops of the spoken phrase "it's gonna rain" are played at slightly different speeds, generating different patterns through phasing.